You can find more information about IPTC here:
http://www.iptc.org
While IPTC is mostly used by professional photographers, news and
wire agencies, it's currently the only standard that allows you to
add all kind of information to your images.
As Tadeusz wrote in his remarkable posting, IPTC information is
stored within your images, and it travels with your images. Even if
you decide to switch your image cataloger some day, all the work
you have put into captioning your images will be save.
Not to mention that IMatch has probably the best IPTC Editor
(user's voices) and fully supports IPTC on various levels. Once the
information has been imported from your images (which is, after an
initial setup) totally automatically, you can use IPTC information
to sort your images, find your images, create contact sheets and
perform batch processing.
You can even use IPTC information in the Web Sites you can create
from within IMatch, to annotate the images on your web gallery.
Since you have also full access to all IPTC information from the
IMatch scripting engine (If you plan to create some cool new
functions with scripting), you can do all sorts of amazing things
with the IPTC information contained in your images.
All of the above is also true for the EXIF information that is
stored in your images by your digital camera. IMatch can handle
that as well (EXIF 2.1/2.2 standard compliant, and soon also able
to handle most of the proprietary EXIF extensions created by all
camera vendors).
Just my two cents ;-)
--
Mario Westphal
Author of IMatch - The Digital Image Management Solution
[email protected]
http://www.photools.com